The most common type of train brake uses compressed air to force a pad against a wheel for braking purposes. The compressed air is supplied by a motor driven air compressor typically located on the locomotive, the compressed air is stored in at least one main reservoir located on the locomotive. Doors, whistles, traction control systems, automatic couplers and window wipers are all mechanical devices which can be operated by compressed air. Air pressure is normally supplied in a range of between 90 and 140 psi and delivered along the length of the trail by an air brake line.
The brake pipe can also be used to replenish reservoirs that are located on separate vehicles that make up a multi-car train. If a single compressor is used time has to be allowed between successive applications for the reservoirs to recharge. Also, the air brake system does not have a partial release capability. Once the brakes are released, the brakes can only be reapplied when the reservoir pressure has recharged to a value higher than the brake cylinder pressure.
A multiple unit train may have two or more compressors located under suitable cars which will supply air to the train through the main reservoir pipe. The operation of the compressors will usually be synchronised via a control wire linked to the compressor governors so that they all operate in unison. Further, compressed air reservoirs may be located under suitable cars providing an air supply to an individual car. A distributor is used on each vehicle to monitor the pressure in the brake pipe. When brake pipe pressure falls, the distributor allows air from the reservoir to pass to the brake cylinders to apply the brake. When brake pipe pressure rises, the distributor releases the air from the brake cylinder and recharges the reservoir for the next application.
A brake release valve is provided on each vehicle in a train and allows the brake to be released manually on that vehicle. Sometimes operated by a lever mounted in a suitable location for access by the crew or in some applications the valve can be operated remotely. Some versions have a bleed hole on a brake isolating cock which performs the same function if it is necessary to isolate the brakes of one car from the rest of the train.
The traditional air brake works well in the hands of a skilled driver but it has a number of shortcomings. The control system relies on the changes in brake pipe pressure to control the application and release of the brakes. This means that a command by the driver to alter the pressure is felt by the front of the train first and then gradually by the rest of the train until it reaches the end. To the novice driver, improper application of the brakes can cause problems during release when leading vehicles in release mode can pull on rearmost vehicles which still have brakes applied.
Electro-pneumatic brake systems have been designed so that they can be added to the traditional air brake system to allow more rapid responses to the driver's braking commands. When an application is called for at one end, the valve opens the brake pipe at the other end so that both ends are exhausting air at the same time. A simple version of this, called an (End of Train device) is used on US freight trains for emergency application.
A basic electro-pneumatic brake system comprises an electrically operated “holding valve” and “application valve” on each car together with control wires running the length of the train. The main reservoir is also connected to each car on the train by a brake pipe. Usually, each vehicle has a compressed air reservoir for the brakes. The electro-pneumatic brake operates independently of the air brake. It uses main reservoir air instead of brake pipe air and the air brake is kept in the release position. The brake is controlled from the same driver's brake valve as the air brake but using new positions to apply and release the brake. Electrical connections attached to the driver's brake valve send commands along the train to the holding and application valves on each car.
The advantage of the electro-pneumatic brake system is that it allows instantaneous reaction on all cars at the same time and it allows small and graduated applications and releases. Electro-pneumatic brakes are not normally used on freight trains because of the diversity of vehicles and the problem of getting an electric signal to transmit at a low voltage down a very long train. Radio control has been suggested, as has fitting each car with a battery.
A pneumatic turbine power supply used to provide electric power for operation of circuitry in an area that a conventional power supply may not be available. The pneumatic turbine has been found to be beneficial in supplying DC power to the End-Of-Train (“EOT”) units. The pneumatic turbines are constructed to provide various voltages powered only with free air delivered from the locomotive and transmitted through the air brake pipe.
A problem that exists with the use of a conventional pneumatic turbine power supply that is coupled to an air brake pipe is that once the air brake pipe line is disconnected or fails, the pneumatic turbine becomes inoperative. If the air brake includes a main reservoir, once the main reservoir exhausts then it is only a matter of time until the pneumatic turbine power supply fails. For example when engaging the braking system an amount of air is consumed. Further, sitting idly in a rail yard may exhaust a reservoir if a conventional pneumatic turbine power supply continues to drawn air or the rolling stock bleed rod is opened.
In a patent disclosure, a battery can be coupled to the turbine to extend the life of the electrical output of the air turbine. However, coupling a battery to a pneumatic turbine does not solve the problem of exhaustion of the air compression in a train's air brake line because the battery may quickly fade if has not been maintained and is not recharged.
There are also many situations that would benefit from a reliable power supply. In particular rolling stock including railcars, box cars, coal cars and could include numerous sensors capable of relying internal and external environment conditions, brake operation, bearing condition, physical location, and so forth.
The prior art references, cited infra, use various systems and methods of implementing a pneumatic turbine based upon compressed air. However, there exists a need for a power supply that can adapted for use on any rolling stock but also provides a means for managing the power supply so that power can provided over an extremely long period of time even if the compressed air supply is not replenished. The instant managed pneumatic turbine power supply system makes it possible to install a multitude of electronic devices and sensors such as gps tracking, cargo temperature sensors, brake sensors, bearing sensors, and so forth to monitor the condition of rolling stock wherein the data obtained can be received by use of wifi, radio frequency, satellite and so forth.